#include "MSAASample.h"
#include "Application.h"
#include "utils.h"
#include "Utility.h"
#include <thread>
namespace RayTracer
{
	void MSAASample::Init()
	{
		curIndex = 0;
		isGenerate = false;
		mImageParam = ImageParam(800, 500, "SSAA.png");

		upColor = vec3(0.5, 0.7, 1.0);
		downColor = vec3(1.0);
		sphereColor = vec3(1.0, 0.0, 0.0);

		sphere1 = std::make_shared<Sphere>(vec3(0, 0, -1), 0.5);
		sphere2 = std::make_shared<Sphere>(vec3(0, -100.5, -1), 100);
		world.add(sphere1);
		world.add(sphere2);
	}

	void MSAASample::Render()
	{
		int width = mImageParam.mWidth;
		int height = mImageParam.mHeight;
		uint8_t* pixels = new uint8_t[width * height * 3];
		int index = 0;
		for (int j = height - 1; j >= 0; j--) {
			for (int i = 0; i < width; ++i) {
				vec3 color = vec3(0.0f);
				for (int s = 0; s < samples_per_pixel; s++)
				{
					auto u = (i + Random01()) / (width - 1);
					auto v = (j + Random01()) / (height - 1);
					Ray r = camera.GetRay(u, v);
					color += RayColor(r, world);
				}
				auto scale = 1.0 / samples_per_pixel;
				color *= scale;
				pixels[index++] = static_cast<uint8_t>(256 * clamp(color.r, 0.0, 0.999));
				pixels[index++] = static_cast<uint8_t>(256 * clamp(color.g, 0.0, 0.999));
				pixels[index++] = static_cast<uint8_t>(256 * clamp(color.b, 0.0, 0.999));
				curIndex++;
			}
		}
		Utils::SaveImage(("Images/" + mImageParam.mName).c_str(), width, height, 3, pixels);
		isGenerate = true;
	}

	void MSAASample::ImGui()
	{
		ImGui::Text(u8"SSAA");
		ImGui::Checkbox(u8"Normal", &isNormal);
		if (isNormal) 
		{ 
			samples_per_pixel = 1; 
		}
		else
		{
			ImGui::SliderInt(u8"Spp",&samples_per_pixel,1,500);
		}
		ImGui::Separator();

		ImGui::Text(u8"Sky");
		ImGui::ColorEdit3(u8"High", &upColor[0]);
		ImGui::ColorEdit3(u8"Low", &downColor[0]);
		ImGui::Separator();
		// Sphere 1
		ImGui::InputFloat3(u8"Sphere1 Center", &sphere1->center[0]);
		ImGui::SliderFloat(u8"Sphere1 Radius", &sphere1->radius, 0.0f, 5.0f);
		ImGui::Separator();
		// Sphere 2
		ImGui::InputFloat3(u8"Sphere2 Center", &sphere2->center[0]);
		ImGui::SliderFloat(u8"Sphere2 Radius", &sphere2->radius, 0.0f, 100.0f);
		ImGui::Separator();

		auto w = (float)mImageParam.mWidth;
		auto h = (float)mImageParam.mHeight;
		auto progress = ((float)curIndex / (w * h));
		ImGui::ProgressBar(progress);
		if (ImGui::Button(u8"Generate")) {
			std::thread t = std::thread([=]() { Render(); });
			t.detach();
		}
		if (isGenerate) {
			auto mTexHandle = Utils::LoadTexture(("Images/" + mImageParam.mName).c_str());
			Application::GetInstance()->SetTexHandle(mTexHandle);
			isGenerate = false;
			curIndex = 0;
		}
		ImGui::SameLine();
		if (ImGui::Button("Reset")) { Reset(); }

	}

	void MSAASample::ShutDown()
	{
		Application::GetInstance()->SetTexHandle(0);
	}

	vec3 MSAASample::RayColor(const Ray & r, const Hitable& world)
	{
		HitRecord rec;
		if (world.Hit(r, 0, infinity, rec))
		{
			vec3 color = 0.5f * (rec.normal + vec3(1, 1, 1));
			return isNormal ? color : sphereColor;
		}

		vec3 unit_direction = glm::normalize(r.direction());
		auto t = 0.5f*(unit_direction.y + 1.0f);
		return (1.0f - t)*downColor + t * upColor;
	}

	void MSAASample::Reset()
	{
		curIndex = 0;
		isGenerate = false;
		mImageParam = ImageParam(800, 500, "SSAA.png");

		upColor = vec3(0.5, 0.7, 1.0);
		downColor = vec3(1.0);
		sphereColor = vec3(1.0, 0.0, 0.0);
		Application::GetInstance()->SetTexHandle(0);
	}
}